As human interface technology laying emphasis on durability, flexibility, and convenience has continued to advance, the importance of flexible electronic devices and material development has been emphasized. Flexible electrodes and materials required to drive a flexible electronic device are also being actively studied. Particularly, demands for transparent flexible electrodes and materials in the industry fields such as touch screen panel (TCP), solar cell, display, etc. are being continuously increased. Therefore, in order to gain economic and technological advantages, there is an urgent need to secure source technology.
ITO (indium tin oxide) is a representative material of transparent flexible electrodes, the price of its raw materials has been gradually increased due to limitation of reserves. Also, ITO is broken when being bent or extended due to its characteristic as oxide, and, thus, it is difficult to apply ITO to flexible electrodes. Meanwhile, a metal nanowire makes it easy to manufacture transparent flexible electrodes and is easy to be mass-produced in solution-phase, resulting in reduction of production costs. Further, the metal nanowire has an excellent mechanical characteristic of being flexibly changed according to deformation of a substrate when bent or extended. Therefore, a lot of studies are being conducted on the metal nanowire as a material of transparent flexible electrodes.
Conventionally, as a silver nanowire synthesis method, a method using poly(vinylpyrrolidone) (PVP) which is a polymeric stabilizer and various organic stabilizers on the basis of an ethylene glycol (EG)-based polyol synthesis method has been mainly studied [B. Wiley, Y. Sun, Y. Xia, Langmuir 21 (2005) 8077.]. However, if the organic stabilizers are used, when a nanowire is applied to an electrode, an organic stabilizer remaining on a surface of the nanowire may cause an increase in resistance and a washing process for removing the organic stabilizer on the nanowire surface needs to be repeated to obtain a high conductivity.